EP0124689B1 - Steel refining method using slag - Google Patents

Steel refining method using slag Download PDF

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Publication number
EP0124689B1
EP0124689B1 EP84101391A EP84101391A EP0124689B1 EP 0124689 B1 EP0124689 B1 EP 0124689B1 EP 84101391 A EP84101391 A EP 84101391A EP 84101391 A EP84101391 A EP 84101391A EP 0124689 B1 EP0124689 B1 EP 0124689B1
Authority
EP
European Patent Office
Prior art keywords
molten steel
slag
steel
refining
stirring
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP84101391A
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German (de)
English (en)
French (fr)
Other versions
EP0124689A1 (en
Inventor
Hideaki Inaba
Shuzi Sakakibara
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Daido Steel Co Ltd
Original Assignee
Daido Steel Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=12067614&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0124689(B1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Daido Steel Co Ltd filed Critical Daido Steel Co Ltd
Priority to AT84101391T priority Critical patent/ATE34184T1/de
Publication of EP0124689A1 publication Critical patent/EP0124689A1/en
Application granted granted Critical
Publication of EP0124689B1 publication Critical patent/EP0124689B1/en
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/072—Treatment with gases
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
    • B22D1/002—Treatment with gases
    • B22D1/005—Injection assemblies therefor
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/0037—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 by injecting powdered material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D3/16—Introducing a fluid jet or current into the charge
    • F27D2003/161—Introducing a fluid jet or current into the charge through a porous element
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D3/16—Introducing a fluid jet or current into the charge
    • F27D2003/167—Introducing a fluid jet or current into the charge the fluid being a neutral gas

Definitions

  • the present invention relates to an improvement in the steel refining method which makes use of a slag.
  • Refining of a steel, particularly desulfurization of the steels by a basic slag, is carried out through the following interfacial reaction between the slag and the molten steel:
  • an inert gas such as argon gas is blown into the vessel containing the molten steel from the bottom of the vessel through a porous plug to stir the molten steel through bubbling thereby to promote the refining.
  • the refining speed can be increased by effecting a stronger stirring by bubbling. It is, however, not allowed to strengthen the bubbling unlimitedly, because the vessel containing the molten steel usually has the form of a ladle, and the height of freeboard, i.e., the wall above the molten metal surface of this vessel is as small as 30 cm and does not exceed 50 cm at the greatest, and therefore, too vigorous bubbling tends to cause an overflow of the slag or molten steel beyond the top of the wall of the vessel. Needless to say, it is not preferred from the viewpoint of effective volume of the vessel to preserve a large freeboard.
  • a blowing of inert gas is made from the upper side of the vessel.
  • This method therefor, will be referred to as "duplex stirring", hereinunder.
  • duplex stirring uses, in addition to the known bubbling from the bottom (main stirring), blowing gas through a submerged lance (auxiliary stirring) into the zone where movement of slag on the molten steel is dull.
  • auxiliary stirring submerged lance
  • a better refining effect can be obtained by using the additional gas in a small amount for auxiliary stirring and a limited amount of gas for main stirring.
  • FIG. 1 showing a conventional stirring
  • an inert gas 2 is blown into molten steel 3 in a ladle 1 through a porous plug 11 provided at the bottom of the ladle 1.
  • the inert gas ascends through the molten steel 3 to stir and circulate the molten steel 3 as indicated by arrows thereby to enhance the contact between the molten steel 3 and a slag 4 covering the latter.
  • a zone in a broken-line circle D is left as a dead zone where the stirring is made insufficiently.
  • a duplex stirring is effected by employing, in addition to the bottom blowing of the inert gas 2 through the porous plug 11, a blowing of the inert gas 2 from the upper side of the ladle 1 by means of an immersed lance 5, thereby to cause a sufficient stirring effect even in the zone D.
  • the position of the blowing of the inert gas from the upper side is changed in accordance with the proceeding of the rate-determining step.
  • the inert gas 2 used for the duplex stirring can contain a desulfurization agent. In this case, however, it is preferred to blow the gas to a certain depth into the molten steel to afford a sufficient time for the formation of the slag and the reaction between the agent and the molten steel.
  • the rates of supply of the inert gas blown from the bottom and the upper side of the ladle, as well as the ratio therebetween, should be determined suitably to attain the strongest stirring effect. It is advisable to make full use of the existing system for blowing from the bottom, while effecting the blowing from the upper side to make up for any insufficiency of the stirring caused by the blowing from the bottom.
  • the following Table shows the rates (units:normal liter/minute) of supply of the inert gas from the bottom and upper side of the ladle in comparison with the conventional stirring which employs the bubbling from the bottom solely, employed in the refining of a batch (80 tons) of molten steel.
  • the duplex stirring in accordance with the invention can be conducted even during the heating of the molten steel by arcs produced by electric power, as in the case of the conventional method.
  • the conventional method had to be conducted in accordance with a pattern or flow which has, for example, the steps of supplying electric power for 10 to 15 minutes with reduced stirring power, stirring at medium strength for 3 minutes, supplying the electric power again for 10 to 15 minutes with reduced stirring power, stirring at medium strength for 3 minutes, supplying as desired the electric power for 5 to 10 minutes with reduced stirring power, and finally effecting a stirring for 4 to 5 minutes.
  • the steel refining method employing the duplex stirring remarkably shortens the time required for the stirring during the suspension of the electric power supply. This in turn decreases the amount of heat which is lost during the stirring and, hence, shortens the time of the next electric power supply. Consequently, considerable time is saved throughout the cycle of the refining process.
  • the method of the invention causes an increase of the rate of supply of the gas per unit time.
  • the blowing time is shortened in the method of the invention, the total consumption of the gas per cycle can be maintained substantially at the same level as that in the conventional method or, if the operation is conducted under adequate conditions, reduced to a level below that in the conventional method.
  • the shortened time for the electric power supply reduces the electric power consumption and, accordingly, contributes remarkably to the reduction of the cost.
  • a batch (80 tons) of molten steel was refined using a basic slag in order to produce a low-sulfur steel having an extremely small sulfur content.
  • the refining was conducted in both methods: namely, the conventional method which employs solely the blowing of the gas from the bottom of the vessel, and the method of the invention which employs the duplex stirring, in accordance with the following operation patterns, respectively.
  • the rate of supply of the gas from the lower side was 200 Nm 3.
  • the inert gas was blown at a rate of 300 Nm' from each of the upper and lower sides.
  • the desulfurization ratio [S]f/[S]s was used as the index for evaluating the effects of these methods.
  • Fig. 3 shows the speed of the desulfurization, i.e., how the desulfurization ratio mentioned above is changed in relation to time. From this Figure, it will be understood that the method of the invention provides a greater desulfurization effect than the conventional method.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Processing Of Solid Wastes (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)
EP84101391A 1983-02-12 1984-02-10 Steel refining method using slag Expired EP0124689B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84101391T ATE34184T1 (de) 1983-02-12 1984-02-10 Verfahren zum feinen von stahl unter verwendung von schlacke.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP21887/83 1983-02-12
JP58021887A JPS59150009A (ja) 1983-02-12 1983-02-12 鋼の精錬方法

Publications (2)

Publication Number Publication Date
EP0124689A1 EP0124689A1 (en) 1984-11-14
EP0124689B1 true EP0124689B1 (en) 1988-05-11

Family

ID=12067614

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84101391A Expired EP0124689B1 (en) 1983-02-12 1984-02-10 Steel refining method using slag

Country Status (5)

Country Link
US (1) US4517015A (enrdf_load_stackoverflow)
EP (1) EP0124689B1 (enrdf_load_stackoverflow)
JP (1) JPS59150009A (enrdf_load_stackoverflow)
AT (1) ATE34184T1 (enrdf_load_stackoverflow)
DE (2) DE124689T1 (enrdf_load_stackoverflow)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE452991B (sv) * 1985-12-20 1988-01-04 Asea Ab Sett och anordning for att effektivisera slagg-/badreaktioner medelst induktiv omroring
DE3817358A1 (de) * 1988-05-20 1989-11-30 Krupp Polysius Ag Vorrichtung zum einbringen von pulverfoermigen reagenzien in eine schmelzpfanne
FR2635789B1 (fr) * 1988-08-29 1993-04-23 Air Liquide American Procede d'elaboration d'acier a faible teneur en azote dans un four poche
JPH0263714U (enrdf_load_stackoverflow) * 1988-10-29 1990-05-14
JPH0557407U (ja) * 1992-01-10 1993-07-30 株式会社豊田自動織機製作所 取付部材の止着構造
US5228902A (en) * 1992-09-03 1993-07-20 Usx Corporation Method of desulfurization in vacuum processing of steel
US5360204A (en) * 1993-09-20 1994-11-01 Keibler-Thompson Corp. Boom and lance for removing slag from crucible
US5472479A (en) * 1994-01-26 1995-12-05 Ltv Steel Company, Inc. Method of making ultra-low carbon and sulfur steel
KR0179394B1 (ko) * 1994-06-06 1999-02-18 도자끼 시노부 함Cr용강의 탈탄 정련방법
JPH10195513A (ja) * 1996-12-27 1998-07-28 Kobe Steel Ltd 金属鉄の製法
AT405188B (de) * 1997-06-16 1999-06-25 Voest Alpine Ind Anlagen Verfahren zum einbringen eines wertstoffs in ein schmelzbad und metallurgisches gefäss zur aufnahme eines schmelzbads
FR2807066B1 (fr) * 2000-03-29 2002-10-11 Usinor Procede de brassage pneumatique du metal liquide en poche
EP2085489A1 (en) * 2008-02-02 2009-08-05 Novaltec Sàrl Fluid microjet system
JP5573424B2 (ja) * 2010-06-30 2014-08-20 Ｊｆｅスチール株式会社 溶鋼の脱硫処理方法

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
LU38343A1 (enrdf_load_stackoverflow) *
SE307627B (enrdf_load_stackoverflow) 1967-02-09 1969-01-13 J Oestberg
US3708599A (en) * 1971-04-22 1973-01-02 Thermal Transfer Corp High temperature apparatus
BE786018A (fr) * 1971-07-09 1973-01-08 Allegheny Ludlum Ind Inc Procede d'injection d'un gaz reactif dans un bain de metal fondu
US3854932A (en) * 1973-06-18 1974-12-17 Allegheny Ludlum Ind Inc Process for production of stainless steel
US3971655A (en) * 1974-08-21 1976-07-27 Nippon Steel Corporation Method for treatment of molten steel in a ladle
US4026698A (en) * 1975-09-18 1977-05-31 Urban Reclamation Technologies, Inc. Removal of tin from molten iron by chlorination, using oxygen to conserve chlorine and to produce tin oxide
DE2737832C3 (de) * 1977-08-22 1980-05-22 Fried. Krupp Huettenwerke Ag, 4630 Bochum Verwendung von im Querschnitt veränderlichen Blasdüsen zur Herstellung von rostfreien Stählen

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
R. WIDDOWSON et al.: "Developpement de techniques d'affinage de l'acier dans une poche préchauffée" *
Stahl und Eisen 101 (1981), p. 852-859 *

Also Published As

Publication number Publication date
US4517015A (en) 1985-05-14
EP0124689A1 (en) 1984-11-14
JPS59150009A (ja) 1984-08-28
DE3471117D1 (en) 1988-06-16
DE124689T1 (de) 1985-08-14
ATE34184T1 (de) 1988-05-15
JPS6213411B2 (enrdf_load_stackoverflow) 1987-03-26

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